Jenna M. Wilson, PhD
A new study found patients with fibromyalgia had greater sleep disturbance and thus poorer accuracy for divided attention tasks than healthy controls.1
“Sleep disturbance is modifiable with behavioral interventions, such as cognitive behavioral therapy, and may be a target for improving sleep quality and cognitive performance among patients with fibromyalgia,” investigators wrote, led by Jenna M. Wilson, PhD, from the department of anesthesiology of perioperative and pain medicine at Brigham and Women’s Hospital in Boston.
Fibromyalgia is a chronic pain condition affecting 4 million US adults, according to the Centers for Disease Control and Prevention (CDC).2 A primary analysis found patients with fibromyalgia demonstrated impaired cognitive performance compared with healthy controls.3 Sleep disturbance, anxiety, and depression—all common conditions for patients with fibromyalgia—are also linked with impaired cognitive performance.1
Investigators conducted a secondary data analysis to evaluate differences in cognitive performance between patients with fibromyalgia and healthy controls. They wanted to see if psychosocial factors caused these differences.
The sample (n = 50) included 24 adults with fibromyalgia and 26 healthy controls with a mean age of 38 years and 90% female. The cohort was 82% White, 8% African American/Black, 8% Asian, and 2% ≥ 1 race.
Participants completed 2 cognitive tasks, as well as the Patient-Reported Outcomes Measurement Information System sleep disturbance, anxiety, depression, and pain severity short forms. Tasks were based on the Bath TAP battery, controlled using the E-Prime II professional software.
Participants completed the cognitive tasks twice, one time in the presence of pain stimuli and the second time without it. Additionally, the order of the testing sessions was randomized. The primary analysis showed there was no significant difference in attention span between patients with fibromyalgia and controls, so the secondary analysis wanted to focus on attentional switching and divided attention tasks.
In the attentional switching task, participants would see a single digit number; sometimes, they would be asked if the number was higher or lower than 5, and other times they were asked if the number was odd or even. When the task stayed the same—for example, 2 odd or even trials—participants performed faster and more accurately than when the request changed between tasks (switching from odd/even to low/high). When participants have a reduction in performance in switch trials, it is referred to as a “switch-cost.”
Investigators particularly looked for reaction time and accuracy between trials. Positive scores reflected faster performance on repeat compared with switch trials, and negative scores reflected better performance on repeat compared with switch trials.
Moreover, the divided attention task required participants to complete 2 tasks simultaneously. Either they looked at a chain of numbers and identified when 3 consecutive odd or even digits were present, or they looked at 2 lines—either vertical or horizontal—and when the 2 lines were presented in different orientations. There were 8-line targets on every set of 80 displays.
Overall, patients with fibromyalgia had worse accuracy for tasks requiring divided attention than controls and sleep disturbance served as a mediator for the group differences in cognitive performance.
“Although we observed a greater switch-cost for accuracy among healthy controls, raw scores on the switching task suggested a slightly larger benefit from repeat trials among healthy controls, whereas patients with fibromyalgia performed similarly across repeat and switch trials,” investigators wrote.
Therefore, the attentional switching task demonstrated healthy controls having a greater switch-cost for accuracy than patients with fibromyalgia (P = .009).
The team observed no group difference in reaction time. Moreover, they also found anxiety and depression were not related to cognitive performance on any task (Ps > .05). Only sleep disturbance was linked with less accuracy on the divided attention task (P = .01) but not related to accuracy or reaction time on the attentional switching task (Ps > .05).
After conducting a mediation analysis, investigators found a significant indirect effect of group difference on divided attention through sleep disturbance (b = -0.05; 95% confidence interval [CI], -0.11 to -0.001). However, the group difference in divided attention was no longer significant when including sleep disturbance in the model (P > .05), suggesting patients with fibromyalgia have poorer accuracy for divided attention, mediated by sleep disturbance.
Limitations stated by the investigators included having most of the sample be female and White, only including patients with fibromyalgia and no other chronic pain conditions, and tasks only measuring attention and executive function and no other types of cognition such as memory.
“Despite these limitations, our findings highlight the importance of considering symptoms of sleep disturbance when investigating cognitive performance, particularly executive attention, among patients with fibromyalgia,” investigators wrote.
- Wilson JM, Meints SM, Edwards RR, Yamin JB, Moore DJ. The role of sleep disturbance in reduced accuracy on a divided attention task among patients with fibromyalgia. Pain Rep. 2024;9(1):e1. Published 2024 Jan 12. doi:10.1097/PR9.0000000000001122
- Moore DJ, Meints SM, Lazaridou A, et al. The Effect of Induced and Chronic Pain on Attention. J Pain. 2019;20(11):1353-1361. doi:10.1016/j.jpain.2019.05.004
- Fibromyalgia. Centers for Disease Control and Prevention. https://www.cdc.gov/arthritis/types/fibromyalgia.htm. Accessed February 9, 2024.